The present invention relates both to a timepiece having a display including indicia representing calendar information such as the particular day of the week, the date of the month and includes with the day presentation a presentation either of "AM" or "PM" and to the apparatus for automatically or selectively controlling the operation of the calendar display through substantially rapid index following each 12-hour and 24-hour period.
Timepieces of the type generally relating to the timepiece of the present invention to be set out hereafter having a day indicator and/or data indicator are known to the prior art. Representative of the prior art are U.S. Pat. Nos. 3,721,085 to R. Zaugg; 3,744,237 to T. Muto; 3,751,901 to H. Meitinger et al.; 3,771,308 to G. Visconti et al.; 3,818,692 to R. Zaugg et al. and 3,911,667 to K. Komiyama.
Each of the aforementioned prior art patents illustrate and describe timepieces having calendar information including day and/or data indicia. The patents more particularly are directed to mechanisms for advancing at scheduled times each form of indicia through an increment of rotation thereby to move the next following indicia at 12 o'clock midnight into position for viewing at an aperture or apertures formed in the face plate of the timepiece. The mechanisms, all which may be differently characterized, are indicated as being of the type whereby the indexing operation is rapidly carried out so that the next succeeding indicia to be brought into alignment with the viewing aperture or apertures assumes its position within the aperture in a substantially rapid time frame for clear reading of that indicia.